Project Summary/Abstract Research on autism spectrum disorder (ASD) in older adulthood lags significantly behind that of research in other age groups, despite similar rates of symptoms (Brugha et al., 2011; Howlin & Moss, 2012; Howlin & Magiati, 2016; Magiati et al., 2014; Michael, 2016; Rabins, 2016). The proposed project examines the feasibility of assessing: (Aim 1.1) ASD characteristics and identifying ASD in older adults and (Aim 1.2) aging outcomes in individuals with elevated ASD characteristics and confirmed ASD relative to neurotypical controls. Specifically, we propose extending the assessment of known challenges associated with ASD in physical health, cognitive performance, and psychological well-being to an older adult sample (Davids et al., 2016; Cassidy et al., 2014; Esbensen et al., 2009; Folstein & Carcache, 2016; Geurts & Vissers, 2012; Mouridsen et al., 2008; Smith et al., 2012). In addition to examining the patterns and outcomes of aging and ASD, the proposed research leverages evidence from the field of personality psychology to identify potential reasons why individuals with ASD are at particular risk for poor aging trajectories. Specifically, the proposed project will test the hypotheses that: (Aim 2.1) meta-analytic associations between Big Five personality traits and ASD (Lodi-Smith et al., under review) replicate in older adults and (Aim 2.2) as in studies of neurotypical individuals and other clinical populations, personality traits are significant, incremental indicators of outcomes of aging in this sample. Using both web- based and lab-based assessments, the present research establishes the feasibility of assessing ASD and aging and tests the replicability of prior findings from personality psychology in older adults with ASD. Completion of the proposed project will begin to establish the patterns, mechanisms, and outcomes of aging in the context of ASD. In doing so, it will lay the foundation for the follow-up longitudinal research necessary to test the development and the directionality of factors impacting aging. Further, the proposed work has the potential for clinical impact by identifying new targets for interventions within this underserved and understudied population.